A diagnal of a polygon is a degment joining the two nonconecutive vertcies of the polygon.How many dianals does a regular octagon have?

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- December 19th 2006, 03:47 PM #1

- December 19th 2006, 03:50 PM #2

- December 19th 2006, 03:51 PM #3

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We know that the octagon has exactly 8 vertices. We are then able to create 5 diagonals from a given vertex.

8*5 = 40; however, there are some repeats. Each diagonal is counted twice since there are 2 points to each diagonal. Thus, 40/2 = 20 is the number of diagonals in a regular octagon.

- December 19th 2006, 03:55 PM #4